HARRISBURG, Pa. -- Civil rights lawyers filed the first known legal challenge Tuesday on behalf of 23 men, women and children seeking to overturn a 17-year-old state law effectively banning same-sex marriage in Pennsylvania, the only northeastern state that doesn't allow it or civil unions.

The lawsuit, filed in federal court in Harrisburg, also asks a federal judge to prevent state officials from stopping gay couples from getting married. It names Gov. Tom Corbett, Attorney General Kathleen Kane and three other officials.

The plaintiffs are a widow, 10 couples and one of the couples' two teenage daughters. They include four couples who were legally married in other states but whose marriages go unrecognized by Pennsylvania.

Same-sex marriage is legal, or soon will be, in 13 states. The lawsuit seeks to legalize it in Pennsylvania and to force the state to recognize the marriages of same-sex couples who wed in other jurisdictions.